<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
    let arrCount = [1,4,5,8,89, 44, 15, 13, 110, 120, 150 ]
    let newCount = []
    arrCount = arrCount.sort(function (a,b) {
      return b-a //a和b比较，如果a»b那就b先添加降序
      })
      arrCount.forEach((item, index)=>{//
    //  forEach为遍历数组的方法 index表示数组第几个元素也就是下标,item表示代表数字
    if (index%2){//用奇偶来判别是头部添加还是尾部添加，单数头部添加，双数尾部添加
    newCount.push(item)//头部添加
     }else {
    newCount.unshift (item)//尾部添加
     }
    })
    
console.log(newCount)
 </script>
 </body>
</html>